By "exfoliating" graphene paper, the material develops pores and wide cracks, which helps the lithium move around more easily. That means the battery can charge much faster.

CourtesyRensselaer Polytechnic Institute

Lithium ion batteries have helped make modern life portable. They're used in everything from cell phones to laptops and cars.

But anyone who has ever been stuck with a dead battery knows they can be problematic.

Now a new study from a team of researchers at the Rensselaer Polytechnic Institute has found a promising technique for building better, longer-lasting batteries.

Energy vs. power

Dr. Nikhil Koratkar is the lead author of the study. Batteries are good at storing energy, but they're not so good at quickly capturing and releasing it, Koratkar says.

In order to do that, batteries need help from another device, called a capacitor. Using the example of an electric car, Koratkar explains how it works:

“The capacitor does all the functions that require high power," he says. "For example, the start-up of the car, and acceleration. The battery takes over when you’re in cruise.”

This trade-off between energy storage and power is the reason batteries can take several hours to charge. But Koratkar's research has revealed a promising way of reconciling the problem.

Best of both worlds

He started with a super-thin material, called graphene paper, and then "exfoliated" it. This process involves blasting it with sound waves, then heating the graphene with a laser or a flash of light.

The resulting structure is full of pores and wide cracks that allow the lithium to move around more easily. The battery can then not only store energy, it can also charge and discharge quickly, too.

“We believe that [you] could combine the the capacitor and the battery into one system," says Koratkar, "That could give you a much cheaper, much more efficient way of making this work.”

So far this technique works in the lab, but Koratkar says more work is needed before it could be scaled up and used commercially.

"Batteries will win"

With this technology, electric cars could be charged in half an hour, or a laptop could be charged in a matter of minutes, says Koratkar.

The National Science Foundation funded the research through a $400,000 grant. Koratkar says there's recently been an increased interest in batteries and he expects them to steadily improve over the next decade.

“Right now the battery car is a little too expensive, but over time, that is going to go down. And as the price of gasoline goes up, at some point there’ll be a crossover, and when that takes place, obviously the batteries will win,” he says.

Koratkar has filed for a patent and plans to search for more funding from a foundation or a major battery manufacturer to further his research.